Because right now they all pay the same tax rate regardless of what they do.

We do not. Some things are taxed higher than others. Some things aren't taxed. Some things are subsidized. Get yourself a resale certificate and never pay sales tax on anything business-related ever again - it's fabulous.

Really reducing externalities would look more like beef being $15/pound

That's policy, though. We subsidize the corn that the cattle eats, we subsidize the cattle.

air travel costing double what it does now

Still policy. Carbon taxes are going to be a bunch of people arguing about what the damage to the environment one air-mile is worth, and what the multiplier of a 737 vs a 787 should be. Try that, by the way, and the airlines are going to sue you if you don't also go after trains, overland freight and shipping (let alone gas taxes).

solar power being cheaper than coal

Part of the reason solar power is approachable now is the Chinese have subsidized the crap out of their panel factories where we had the catastrophe-that-was-Solyndra. Now you're talking trade: you're going to penalize mined-in-West-Virginia coal but you're going to favor Chinese solar panels?

and locally produced goods being more competitive because of lower transportation costs.

Ever bought a $30 chicken? I have. It was grown by a farmer 150 miles away, and it was his break-even price on what producing a chicken in a humane way that feeds his family. It was also frozen. Compare and contrast: I can get that size chicken rotisserie-hot at the supermarket for $4. That's the problem: the $26 delta between the family chicken and the factory chicken is a lot more than transportation costs. And if you try to fix these things with one-size-fits-all tax policy you're gonna break things, piss people off and set up a whole different group of people to succeed.